HIV

Question 1

what does HIV target in general

Answer 1

immune cells

Question 2

what are the two tyoes of HIV

Answer 2

HIV 1 - more commonly associated with AIDS

HIV 2 - rarer and restricted to Africa and asia

Question 3

specifically, what does HIV 1 target

Answer 3

CD4+ cells such as macrophages, T helper cells and dendritic cells

Question 4

what is the function of cd4

Answer 4

helps immune cells communicate with each other when fighting foreign pathogens

Question 5

how can people be naturally immune to HIV

Answer 5

hiv needs not only to bind to cd4 but also a coreceptor before it can invade a cell. if someone has a mutation which alters the shape of their co receptor then HIV cannot invade

Question 6

describe HIV as a pathogen

Answer 6

single stranded RNA retrovirus (uses reverse transcriptase to copy itself)

Question 7

how does HIV replicate itself

Answer 7

invades immune cell then copies its RNA via reverse transcriptase. This proviral DNA then integrates into the immune cells (host) DNA ready to be replicated. every time the host is exposed to infection, as the t cell replicates, so does the HIV

Question 8

how does HIV typically spread from person to person

Answer 8

sexual
parenteral (needlestick)
vertical (mother to child)

Question 9

what happens as soon as a person is infected with HIV

Answer 9

dendritic cells eat infection from mucosa and take it to nearest lymph node, the infection then takes over all the immune cells in the lymph node leading to a very high viral load in acute infection

Question 10

what are the symptoms of acute infection of HIV

Answer 10

flu like symptoms similar to glandular fever

Question 11

how long is the acute phase

Answer 11

12 weeks

Question 12

what happens to the viral load from acute and chronic phases

Answer 12

decreases as the hosts immune system attempts to control replication and counterattack

Question 13

how long can the chronic phase last for

Answer 13

2-10 years

Question 14

what happens to t cells in the chronic phase

Answer 14

as the virus increases the t cells decrease killing roughly 2 billion cells per day
you end up with around 500 T cells which is just enough to fight infections even though they may be more sever

Question 15

what happens if t cells drop to roughly 200-500 cells

Answer 15

lymphadenopathy
hairy leukoplakia (white patches on tongue caused by EBV)
oral candida

Question 16

what happens if the t cells drop below 200

Answer 16

immune system severely compromised leading to AIDS

persistent fever fatigue weight loss and diarrhoea with HIV count rising

Question 17

what are the AIDS defining conditions

Answer 17

recurrent bacterial pneumonia
pneumocystis pneumonia
fungal infections (candida of the oesophagus)
tumours (kaposis sarcoma, primary lymphoma of the brain)

Question 18

what is the most common mode of transmission

Answer 18

male to male in developed countries
male to female in developing countries
IVDU

Question 19

how can you diagnose HIV

Answer 19

antibody testing (elisa or rapid tests)
antibody (antiHIV) antigen (p24) testing
RNA/ DNA test

Question 20

treatment

Answer 20

antiretroviral therapy (triple therapy)

Question 21

transmission is unlikely if

Answer 21

viral load is less than 400 copies /ml

Question 22

what are the main confirmatory tests done for hiv

Answer 22

HIV antibody differentiation immunoassay

western blot

Question 23

what do you monitor after treatment initiation

Answer 23

cd4 count viral rna load

cd4/cd8 ratio

Question 24

what are the main types of anti retroviral drugs

Answer 24

NRTI 
NNRTI
nucleotide analogues 
protease inhibitors 
integrase inhibitors 
fusion inhibitor
ccr5 antagonist

Question 25

most NRTIs end in

Answer 25

ine

Question 26

most proteasi inhibitors end in

Answer 26

avir

Question 27

most integrase inhibitors end in

Answer 27

gravir

Question 28

what defines AIDS

Answer 28

cd4<200

aids defining conditions

Question 29

what are the aids defining conditions

Answer 29

primary lymphoma of the brain
pneumocystis pneumonia
cerebral toxoplasmosis

Question 30

what virus causes kaposis sarcoma

Answer 30

hhv8